The primary objective of this research is to gain further insights into the mechanisms of protein secretion and its control, with attention focused on the Golgi complex and the participation of each of its components in the secretory process. The approach proposed to achieve this goal is: (a) to analyze the sites, pathways and control mechanisms of secretion of pituitary hormones, especially the glycoprotein hormones; (b) to attempt to work out in detail the flow diagram of secretory products within the Golgi complex; and (c) to determine the distribution of various enzymes (adenyl cyclase, glycosyl transferases) among components of the Golgi complex. The approach used to investigate these problems will combine the classical methods of experimental endocrinology with electron microscopy, autoradiography, enzyme cytochemistry and cell fractionation. BIBLIOGRAPHIC REFERENCES: Cheng, H, and Farquhar, M.G. Presence of adenylate cyclase in Golgi and other fractions from rat liver. I. Biochemical determination. J. Cell Biol., 70: 660-670, 1976. Cheng, H., and Farquhar, M.G. Presence of adenylate cyclase in Golgi and other fractions from rat liver. II. Cytochemical localization within Golgi and ER membranes. J. Cell Biol., 70: 671-684, 1976.